This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
Hose fittings are used to connect a fluid line or hose to various types of industrial equipment and machinery via the equipment connection ports or manifolds. A hose fitting typically has two ends: one end generally defines the hose connection end and the other end generally defines the equipment connection end. In one type of hose fitting, a stem is provided having a first end, the equipment connection end, and a second end, the hose connection end, wherein the second end includes a shell placed over the stem. The first end of the stem may be threaded or may include a nut placed thereon for engaging the equipment. The external surface of the second end of the stem typically engages the internal surface of a hose, while the internal surface of the shell engages the external surface of the hose.
During the manufacture of such hose fittings, a wrenching surface, such as a hexagonal surface, is generally provided on the outer portion of the shell. A wrench, or other suitable tool, may be used to engage the wrenching surface while securing the equipment connection end of the fluid coupling to the equipment. This maintains stability of the hose connection end and prevents damage to the hose and/or its connection to the coupling by a resulting tendency to twist during the securing procedure. The hexagonal surface is generally provided at a different horizontal location of the fluid coupling than the horizontal location of a joined portion of the stem and the shell. Common methods of joining the coupling pieces include crimping, staking, swaging, etc.
Some hydraulic hose fittings require two hexes on the fitting. One hexagonal is on a swivel nut and the second hexagonal is solid and formed the stem. When the fitting is attached to a manifold, one wrench rotates the swivel nut and a second wrench prevents the stem from rotating. The inner diameter of the swivel nut is smaller than the hexagonal size on the stem. There are two common designs for this type of fitting. In the first design, the stationary hexagonal on the stem is created by machining hexagonal bar stock or forging the hexagonal into the stem. The connection end of the fitting is left as an open tube. A tube nut slides over the open end of the tube and a larger outer diameter part is brazed onto the end of the tube to retain the swivel nut. In the second design, the stem is machined out of hexagonal bar stock or forged with a hexagonal on the stem. The shoulder that retains the swivel nut is machined solid onto the stem so no brazing is required. The swivel nut is then crimped over the shoulder on the stem so it is retained by the shoulder. Furthermore, hexagonal wrench flats have limited flats for engaging a wrench.
Brazing two stem sections together requires an additional process step which increases cost and creates a potential leak at the brazed connection. Crimping the swivel nut onto the stem requires an additional process step which increases cost and the crimped nut has lower max torque values compared to tube nut designs.
Thus, there is an ongoing need for improved hose fittings, and methods of manufacturing such, with fewer process steps, and increased torque ratings for such fittings, such needs met at least in part with embodiments according to the following disclosure.